title: High resolution grazing-incidence in-plane x-ray diffraction for measuring the strain of a Si thin layer.
abstract: We have measured the strain of a thin Si layer deposited on a SiGe layer using a high resolution x-ray diffraction system. The Si layer was deposited on the SiGe layer in order to introduce a tensile strain to the Si layer. To measure the in-plane lattice constant accurately, we have employed so-called grazing-incidence in-plane diffraction. For this measurement, we have made a new five-axis x-ray goniometer which has four ordinal circles (ω, 2θ, χ, φ) plus a counter-χ-axis for selecting the exit angle of the diffracted x-rays. In grazing-incidence geometry, an incident x-ray is focused on the sample surface in order to obtain good diffraction intensity even though the layer thickness is less than 5 nm. Because diffracted x-rays are detected through analyzer crystals, the diffraction angle can be determined with an accuracy of ± 0.0003°. This indicates that the strain sensitivity is about 10( - 5) when we measure in-plane Si 220 diffraction. Use of x-ray diffraction could be the best standard metrology method for determining strain in thin layers. Furthermore, we have demonstrated that incident/exit angle selected in-plane diffraction is very useful for height/depth selective strain determination.
authors.affiliation: Rigaku Corporation, 3-9-12 Mastubara-cho, Akishima 190-8666, Japan. omote@rigaku.co.jp
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Omote
mesh_terms: D000465:Algorithms; D055119:Elastic Modulus; D008422:Materials Testing / Q000379:methods*; D008567:Membranes, Artificial; D012825:Silicon / Q000737:chemistry*; D013314:Stress, Mechanical; D013499:Surface Properties; D014961:X-Ray Diffraction / Q000379:methods*
chemical_list: D008567:Membranes, Artificial; D012825:Silicon